CVE-2026-34415
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-34415 is a critical-severity Incomplete List of Disallowed Inputs (CWE-184) vulnerability. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 12% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34415 is an incomplete input validation vulnerability in the elFinder connector endpoint of Xerte Online Toolkits versions 3.15 and earlier. The issue arises from an incorrect regex pattern that fails to block PHP-executable extensions such as .php4, allowing potentially malicious file uploads.
Unauthenticated attackers can exploit this flaw in combination with separate authentication bypass and path traversal vulnerabilities to upload malicious PHP code, rename it with a .php4 extension, and execute arbitrary operating system commands on the server. The vulnerability has a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity with high confidentiality, integrity, and availability impacts.
Mitigation is available through patches in the Xerte Online Toolkits repository, including commits 02661be88cc369325ea01b508086bde7fbfec805, 17e4f945fe6a3400fa88c01eda18c1075ee4a212, and 507d55c5e91bf9310b5b1c7fad8aebfef902ad23. The issue is tracked at https://github.com/thexerteproject/xerteonlinetoolkits/issues/1527, and a proof-of-concept for remote code execution is published at https://github.com/bootstrapbool/xerteonlinetoolkits-rce. Affected installations should apply these updates promptly.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25069
Vulnerability Data
Xerte Online Toolkits versions 3.15 and earlier contain an incomplete input validation vulnerability in the elFinder connector endpoint that fails to block PHP-executable extensions .php4 due to an incorrect regex pattern. Unauthenticated attackers can exploit this flaw combined with authentication…
more
bypass and path traversal vulnerabilities to upload malicious PHP code, rename it with a .php4 extension, and execute arbitrary operating system commands on the server.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 2 hardening rules · 1 OS baseline
V3.5.2V4.4.2V16.2.5
Mitigating Controls (NIST 800-53 r5) AI
SI-10 requires validity checks on inputs, which structurally replaces incomplete deny-lists with complete allow-list or sanitization logic.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require complete, positive input validation instead of incomplete denylists.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can discover missing input checks, but does not prevent the weakness during development.
Application security requirements can mandate complete input validation rules, but the control itself does not prescribe how to build those rules.
Secure architecture principles include robust input validation design, yet the control is broader than this single weakness.
Secure coding standards directly require exhaustive allow-lists or complete deny-lists for inputs, addressing the root cause of incomplete disallowed-input lists.